San Diego State’s opening play last week against UNLV was a run, with quarterback Christian Chapman handing off to junior tailback Juwan Washington.

Washington tucked the ball away, cut to his left and tried to get outside. He was tackled for a 2-yard loss. At least that’s where the officials spotted the ball.

Washington was met on the play by a wall of UNLV defenders, who pushed him back nearly 10 yards before the play was whistled over.

It epitomized SDSU’s rushing struggles against the Rebels, who posted a shocking 27-24 win. It also represented a running game that has gone backwards this season.

“We’re accustomed to ripping off some big runs and big plays and we haven’t consistently been able to do that,” SDSU offensive coordinator Jeff Horton said. “That’s put some pressure on us offensively, trying to piecemeal (things) together. We’ve had to fight for every yard, every point, that we’ve gotten this year. ... It certainly hasn’t been pretty at times. That’s probably an understatement.”

After three straight years ranked among the nation’s top 20 teams in rushing, the Aztecs this year are ranked 70th (out of 130 teams) with 166.1 yards a game.

With the spread popularized during this pass-happy era of college football, SDSU’s run-dominated offense has been stubbornly persistent in its “three yards and a cloud of dust” philosophy.

While a seemingly endless number of short runs does little to quicken the pulse of the modern-day fan, there was a saving grace for the Aztec attack. Success — a school-record three straight seasons with double-digit wins — for one thing. And it came from an offense that regularly featured what could be termed “explosive runs,” carries that go for long gains that, with any luck, resulted in touchdowns.

SDSU fans watched the nation’s past two rushing leaders — D.J. Pumphrey and Rashaad Penny — carrying the football with Washington waiting in the wings.

Such runs have been largely absent this season during an inconsistent campaign for SDSU (7-3, 4-2 Mountain West), which comes into Saturday’s game at Fresno State (8-2, 5-1) clinging to slim hopes for a conference title.

As far as popping big scoring runs:

• In 2016, SDSU had 17 explosive runs (20 yards or more) that went for touchdowns. Pumphrey had 10, Penny had three and Washington had four.

• Last year, SDSU had 16 explosive runs for TD. There were 14 by Penny — including two such runs in five different games — and two more by Washington.

• Through 10 games this season, the Aztecs have had just four explosive runs. Washington had a 20-yard TD run against Sacramento State and 34- and 50-yard TD runs at New Mexico. Freshman Jordan Byrd had the other one — a 72-yard TD run at Boise State.

One has to wonder if things would be different had Washington stayed healthy this season. He missed half the season after fracturing his clavicle in Week 4 against Eastern Michigan.

Not only did that remove SDSU’s biggest home run threat from the field, it thrust other players — like Byrd, a true freshmen, sophomore Chase Jasmin and redshirt freshman Chance Bell — into significant roles when they otherwise would have been seasoned more slowly.

“The thing you find with backs is when they’re young and they haven’t been in there a lot inexperience-wise,” Horton said, “they don’t understand tempo of runs sometimes. It’s just, ‘I get the ball and go as fast as I can and see what happens.’ ... Because of your tempo, that creates some seams and then you hit them.

“Rashaad and Donnel and those guys were masters at doing that. But they both had a chance to learn (in backup roles).”

The inability to break those big scoring runs has shown on the scoreboard. SDSU ranks 113th in the country with 22.4 points a game. The Aztecs’ struggle to run the ball has been exacerbated by a now veteran offensive line’s inability to consistently control the line of scrimmage.

“I think the line of scrimmage is a lot more important than people give it credit for,” SDSU head coach Rocky Long said. “If you can control the line of scrimmage, your chances of winning are dramatic. If you can’t control the line of scrimmage and (your opponent can), you’re going to lose most every time. ...

“If you’re not winning the line of scrimmage, the skill guys can’t win the game for you. If you’re winning the line of scrimmage, the skill guys will win the game for you. I mean, it’s a really simple fact.”

It’s been a frustrating fact of life for SDSU offensive line coach Mike Schmidt that the offensive line hasn’t been as strong as everyone expected entering the season.

“I’ve been trying to figure that out all year,” said Schmidt, who has had to juggle things some because of injuries. “The lineup hasn’t all been the same, but we’re not playing as together as we need to. There’s inconsistency, and I don’t think we’re playing as tough or as physical as we need to.”

Schmidt said he doesn’t think they’ve regressed on the O-line, but he admits the group has not played as well as it did late last year. And penalties have come at seemingly the most inopportune moments.

It appeared Washington’s return — highlighted by the too long runs at New Mexico — might signal a turning point. Then the Aztecs went out and struggled against UNLV, gaining just 89 yards on 34 carries (2.6 ypc). Half the plays went for 1-yard or less. The closest the Aztecs came to a big play was a 27-yard run by Washington late in the third quarter. It was the team’s only double-digit rush of the game.

More bad news came this week when it was learned that two starting linemen would be out against Fresno State. Sophomore left tackle Tyler Roemer has been suspended indefinitely for a violation of team rules and sophomore right guard Keith Ismael is under concussion protocol.

Amid this backdrop, Schmidt said: “We’ve got to find a way to get our damn swagger back.”

“The only way you do that is you dominate people,” he said. “We’ve haven’t done that consistently enough this year, so maybe guys are questioning their ability, not as confident as you need to be up front.

“You’ve got to be a confident guy to come off the ball and really get the job done. ... We’ve got some things to overcome here.”

POPPING THE BIG RUN

The number of explosive runs (20 yards or more) for a touchdown for San Diego State has been substantially reduced this season compared to the previous two years: